1. Field of the Invention
The present invention relates to a system and method for enhancing media access control (MAC) address privacy in a multi-hop wireless network, comprising providing at least one node which generates a temporary MAC address for itself for use in the network by at least one other node, and which ensures that the temporary MAC address is unique among other nodes in the network prior to using the temporary MAC address.
2. Description of the Related Art
Wireless communication networks, such as mobile wireless telephone networks, have become increasingly prevalent over the past decade. These wireless communications networks are commonly referred to as “cellular networks”, because the network infrastructure is arranged to divide the service area into a plurality of regions called “cells”. A terrestrial cellular network includes a plurality of interconnected base stations, or base nodes, that are distributed geographically at designated locations throughout the service area. Each base node includes one or more transceivers that are capable of transmitting and receiving electromagnetic signals, such as radio frequency (RF) communications signals, to and from mobile user nodes, such as wireless telephones, located within the coverage area. The communications signals include, for example, voice data that has been modulated according to a desired modulation technique and transmitted as data packets. As can be appreciated by one skilled in the art, network nodes transmit and receive data packet communications in a multiplexed format, such as time-division multiple access (TDMA) format, code-division multiple access (CDMA) format, or frequency-division multiple access (FDMA) format, which enables a single transceiver at a first node to communicate simultaneously with several other nodes in its coverage area.
In recent years, a type of mobile communications network known as an “ad-hoc” network has been developed. In this type of network, each mobile node is capable of operating as a base station or router for the other mobile nodes, thus eliminating the need for a fixed infrastructure of base stations.
More sophisticated ad-hoc networks are also being developed which, in addition to enabling mobile nodes to communicate with each other as in conventional ad-hoc networks, further enable the mobile nodes to access a fixed network and thus communicate with other types of user terminals, such as those on the public switched telephone network (PSTN), and on other networks such as the Internet. Details of these advanced types of ad-hoc networks are described in U.S. Pat. No. 7,072,650 entitled “Ad Hoc Peer-to-Peer Mobile Radio Access System Interfaced to the PSTN and Cellular Networks”, issued on Jul. 4, 2006, in U.S. Pat. No. 6,807,165 entitled “Time Division Protocol for an Ad-Hoc, Peer-to-Peer Radio Network Having Coordinating Channel Access to Shared Parallel Data Channels with Separate Reservation Channel”, issued on Oct. 19, 2004, and in U.S. Pat. No. 6,873,839 entitled “Prioritized-Routing for an Ad-Hoc, Peer-to-Peer, Mobile Radio Access System”, issued on Mar. 29, 2005, the entire content of each being incorporated herein by reference.
As the deployment of the wireless networks grows rapidly, the issue of identity privacy for the wireless users is becoming one of the major concerns in the context of wireless security. Currently, fixed Media Access Control (MAC) address identifiers for user mobile devices or nodes cannot be hidden with ease from eavesdroppers and other users in a wireless network, due to the fact that fixed MAC address identifiers cannot be adequately encrypted in the current security design. Consequently, if a mobile host sends packets from several locations, an eavesdropper might be able to track that node even if other packet security measures have been used.
In Universal Mobile Telephone Standard (UMTS) and Global System for Mobile Communications (GSM) cellular telephone networks, a mechanism for user identity confidentiality has been used in which a user is normally identified by a Temporary Mobile Subscriber Identity (TMSI). In this mechanism, a TMSI is assigned by a Visited Location Register (VLR), which is located at the base station. The TMSI, in this regard, has local significance only in the location or routing area in which the user is registered, and the VLR will maintain a mapping between TMSI and user's permanent International Mobile Subscriber Identity (IMSI).
A need remains, however, for mechanisms and schemes for MAC address privacy within infrastructure-based multi-hop ad-hoc wireless networks. The present invention provides such a scheme.